基于非线性能量收集的全双工认知中继网络的联合优化方法

Joint optimization method of full-duplex cognitive relay network based on nonlinear energy harvesting

针对信息传输过程的时间消耗和信道估计误差对网络能效的影响,提出了一种基于非线性能量收集的全双工认知中继网络的联合优化方法。所提方法是在中继采用非线性能量收集并考虑非完美信道状态信息(CSI)的情况下,首先通过将能效非凸优化问题转化为两个凸的子优化问题,从而求出次用户和中继的传输功率以及收集的能量;其次,在保证主用户干扰门限以及最优传输功率非负的情况下,求出传输的信道容量范围;最后,将传输功率代入表达式得到关于时间的目标函数,并利用海森矩阵证明该目标函数为凸函数,进而求出最优传输时间以及功率分割因子,最终得出能效最优解。实验结果表明,在相同条件下,所提联合优化方法的能效相较于仅优化传输功率的能效提升了约84.3%;同时验证了信道估计误差因子为0.01时,所提方法的网络能效降低了约1.9%。

Aiming at the influence of the time consumption of the information transmission process and the channel estimation error on the energy efficiency of the network, a joint optimization method of full-duplex cognitive relay network based on nonlinear energy harvesting was proposed. The proposed method was based on the use of nonlinear energy harvesting in the relay and consideration the imperfect Channel State Information(CSI). Firstly, the energy efficiency non-convex optimization problem was transformed into two convex sub-optimization problems to obtain the transmission power of the secondary user and the relay as well as the collected energy. Secondly, under the condition that the primary user interference threshold was guaranteed and the optimal transmission power was non-negative, the range of transmission channel capacity was obtained. Finally, the transmission power was substituted into the expression to obtain the time related objective function, and the Hessian matrix was used to prove that the objective function was a convex function, the optimal transmission time and power splitting factor were calculated, and the optimal solution of energy efficiency was obtained.Experimental results show that under the same conditions, the energy efficiency of the proposed joint optimization method is about 84. 3% higher than that of only optimizing the transmission power. At the same time, it is verified that when the channel estimation error factor is 0. 01, the energy efficiency of the network is reduced by about 1. 9% by using the proposed method.